docs: def add_job(self, job_name, job_id=None):
          """ Create a new, empty Job. """
          logger.debug('Creating a new job named {0}'.format(job_name))
          if not self._name_is_available(job_name):
              raise DagobahError('name %s is not available' % job_name)
  
          if not job_id:
              job_id = self.backend.get_new_job_id()
              self.created_jobs += 1
  
          self.jobs.append(Job(self,
                               self.backend,
                               job_id,
                               job_name))
  
          job = self.get_job(job_name)
          job.commit()